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Monday, 25 November 2013

New Cochrane review examines the effectiveness of smoking cessation strategies in young people

This post was written by Andrew Jones for the Mental Elf, you can find the original here.

Worldwide, around 100 000 young people take up smoking every day and approximately 1 in 4 young people in the UK and USA smoke regularly. Although these figures have been falling over the last 20 years, they still represent a major public health concern. Evidence suggests that addiction to nicotine develops quickly in adolescence, and most adult smokers will acquire the habit during this time. Furthermore, whilst the global disease burden is primarily focused on problems in adulthood, young smokers can suffer complications in lung growth and function.

The majority of adolescent programs focus on the prevention of smoking uptake (which have been covered by previous systematic reviews), however there are some programs aimed at helping young people to give up once they have started smoking. These interventions may prove useful as many of these individuals report that they often try to quit without help.
A recent review published by the Cochrane Collaboration set out to examine the effectiveness of strategies that might help young people to quit smoking. This was an update of a Cochrane review conducted in 2006.

Methods

The authors targeted three types of studies; randomised controlled trials (RCTs), cluster-randomised controlled trials (C-RCTs) and controlled trials, comparing an intervention to a control condition in individuals aged less than 20 years old, who were regular smokers. To be included, interventions had to be aimed at helping young people to stop smoking and have follow up data for at least 6 months.

The interventions ranged from simple pharmacotherapy through to more complex strategies encompassing several active components and targeting organisations such as schools and communities. Control conditions included; no intervention, delayed intervention beyond the last date of data acquisition, general tobacco information and information on stopping smoking.

The authors searched the Cochrane Tobacco Addiction Group Specialised Register to identify relevant trials. Where possible, they also searched unpublished literature and contacted manufacturers of smoking cessation products. They found 28 relevant studies for inclusion (consisting of approximately 6000 young smokers in total). The primary outcome was smoking status after at least six months follow-up among those who smoked at baseline.

The authors pooled groups of studies that they considered to have similar interventions, comparison groups and participants. This led to three main types of intervention, which were those based on: (1) Transtheoretical Model of Change (TTMC), (2) Psychosocial interventions including motivational enhancement and (3) the Not-on-Tobacco program (NoT).

• TTMC is a model of intentional change and focuses on the decision making of an individual.
• Psychosocial interventions involve motivational interviewing, relapse prevention and resisting social and cultural pressures.
• NoT program is a gender-specific group program implemented in schools or communities, drawing on social cognitive theory.

Results

In order to measure the treatment effect for each individual study, the authors used risk ratios (RR).

Pooled results from 3 TTMC studies demonstrated that there was a significant effect in favour of the intervention on smoking cessation (RR = 1.56, 95% CI 1.21 – 2.01).

Pooled results from 6 NoT interventions demonstrated a marginally statistically significant effect of the intervention (RR = 1.31, 95% CI 1.01 to 1.71). However, none of the six NoT interventions demonstrated significant improvements individually.

Other types of treatment were identified. Four studies used internet and/or computer based interventions however, none relied solely on this technique making it impossible to disentangle treatment effects. One trial examining Nicotine Replacement Therapy and two trials examining pharmacotherapy (Buproprion) demonstrated no beneficial effects on adolescent smoking cessation.

Conclusions

The results of this Cochrane review suggest that interventions which are designed to help adolescent smokers to quit are generally effective. In particular the authors recommend

‘programmes that combine a variety of approaches, including taking into account the young person’s preparation for quitting, supporting behavioural change and enhancing motivation show promise’.

Limitations

However, the authors also note various issues. Firstly, many of the studies were at a high risk of selection bias, in which groups or individuals were not randomly allocated. Secondly, several individual studies had low statistical power, which the authors suggest may contribute to the null effects of individual NoT studies. Finally, many studies did not use gold standard techniques including biochemical measures of smoking cessation or sustained abstinence measures. These issues reduce the confidence in wider application of these results.

To conclude, there is some evidence to suggest that complex interventions may be effective in increasing smoking cessation in young smokers. Future research should focus on direct comparisons between effective treatments.